Chain of Thought

Chain of thought (CoT) in AI UX is a pattern that reveals intermediate reasoning, plans, or tool steps so users can audit how the answer was produced. It may appear as expandable Thought, Activity, or step traces (not always raw model tokens) and supports trust, debugging, and learning.

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Interactive demo

A store marks up a $40 jacket by 25%, then takes 20% off during a flash sale. What does it cost now?

It's $40, the same as before the sale. A 20% discount only offsets a 25% markup when it lands on the marked-up price, which is what happens here.

Overview

The design problem

How might we let people audit an answer’s reasoning without turning every reply into a wall of text?

Use this pattern

When the reasoning itself carries decision value

  • Math, logic, and multi-step problems where the path to the answer matters as much as the result.
  • Agentic or coding tasks where people need to follow tool calls and intermediate decisions.
  • High-stakes or regulated work where an audit trail helps people verify before they act.
  • Educational tools where seeing the steps is the point, not just the final number.

Avoid this pattern

When steps add noise without an audit need

  • Casual Q&A where showing reasoning adds noise and latency for no decision value.
  • Regulated domains where incorrect step narratives create liability even when the final answer is fine.
  • Cases where the model’s “thoughts” are unreliable after-the-fact stories rather than true traces.

States

Design the disclosure lifecycle, not only a static thinking block parked under every answer.

Chain of thought disclosure lifecycle

Loading diagram…

  1. 01

    Working

    The assistant works through the problem. Nothing is shown yet beyond a brief in-progress cue.

  2. 02

    Collapsed

    Reasoning finishes and condenses into a compact control with a step count. It stays closed by default.

  3. 03

    Expanded

    The person opens the disclosure. Numbered steps appear in the order the assistant used them.

  4. 04

    Answered

    The final answer renders below the disclosure and stays visible whether the panel is open or closed.

  5. 05

    Reviewed

    The person scans the steps to spot check the logic before acting on the number or claim.

  6. 06

    Re-collapsed

    Closing the panel keeps the thread scannable. The steps remain available if anyone needs them again.

Key UX elements

The parts that must be present for step-by-step reasoning to build trust instead of clutter.

Trigger

Show reasoning only when it earns its place.

Turn on the disclosure for multi-step math, agentic runs, or high-stakes claims. Skip it for a one-line answer to a simple question.

Disclosure

Collapse the reasoning behind a named control.

A compact Reasoning row with a step count beats an open block of thinking text under every reply.

Steps

Number the intermediate steps in order.

Each step should read as one discrete move, a calculation, a lookup, a decision, not a paragraph of prose.

Answer

Keep the final answer separate and always visible.

The answer should stand on its own whether the reasoning panel is open or closed, not depend on someone expanding it first.

Collapse

Let people close the panel again.

Reasoning is a reference, not a permanent fixture. Collapsing it back keeps the thread scannable once someone has checked the steps.

Progressive

Match depth to the task, not the model.

A one-line summary suits simple lookups. Full numbered steps suit math, planning, or tool use. Avoid full traces on every reply by default.

Anti-patterns to avoid

  • Dumping wall-of-text “thinking” with no collapse or summary.

  • Presenting fabricated step-by-step justifications as factual audit trails.

  • Hiding tool calls users need while showing only decorative CoT prose.

  • Forcing CoT open by default on every message in a dense chat.

How products use it

ProductImplementation
ChatGPTThought / Activity surfaces for deeper runs without crowding the main answer.
ClaudeExtended thinking and tool traces can be inspected for agentic or hard tasks.
GeminiShows planning or research steps on complex queries alongside the answer.
Cursor / coding agentsExposes plan and file/tool steps so developers can follow agent work.

Implementation

Copy this prompt to generate a production-ready implementation in Cursor, Claude Code, Lovable, or any AI coding agent.

Generate a production-ready implementation of the "Chain of Thought" AI interface design pattern.

Pattern Definition:

Frequently asked questions

What is chain-of-thought UX in AI products?

Chain-of-thought UX means showing selected intermediate reasoning, plans, or tool steps so users can understand how the answer was produced, usually behind an expandable Thought or Activity control rather than as the only answer.

Should every AI reply show its reasoning?

No. Show reasoning for complex, high-stakes, or agentic tasks where users need an audit trail. Keep it collapsed or off for simple answers to avoid cognitive and visual load.

Is visible CoT the same as the model’s hidden chain of thought?

Not always. Product CoT is a designed disclosure of plans, tools, or summaries. Model-internal tokens may differ and can be incomplete or stylized, so treat UI reasoning as an aid, not a legal proof.

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